Means for exploding bombs



W Raye/C Beryl/QM BY Jan. 31, 1961 R. c. BERGVALL 2,969,736

MEANS FOR EXPLODING BOMBS Filed Nov. 7, 1941' Fiji.

WITNESSES: I l INVENTOR 5 t ATTORNEY 7 2,969,736 MEANS FOR EXPLODING BOMBS Royal C. Bergvall, Wilkinsburg, Pa., assignor to Westinghouse Electric Corporation, a corporation of Pennsylvania Filed Nov. 7, 1941, Ser. No. 418,151

7 Claims. (Cl. 102-2) My invention relates to explosives and has particular relation to explosives to be projected or dropped from aircraft at a target on the ground.

The damage caused by aircraft explosives which are set off a distance of the order of ten or twenty feet above a target on the ground is far greater than that caused by explosives which are set off after contact with the target. In accordance with the teaching of the prior art of which I am aware the detonation of aircraft explosives to be set off above ground is controlled by photoelectric devices. The explosive is provided with a source and a photoelectric cell. When the explosive is near the target, light is reflected by the target to the cell and the explosive is set off.

The basis of such arrangements is that there is a surface at the target which reflects light. Since many targets do not reflect light the photoelectric control in many situations fails to function. On occasions a bomb containing the photoelectric control may be suspended from an airplane which is flying over a specular surface such as a body of water. Sunlight reflected from the surface may impinge on the photoelectric cell causing the bomb to explode prematurely.

It is accordingly an object of my invention to provide a reliable control system for setting off an explosive which is dropped from an aircraft a short distance above the target.

A further object of my invention is to provide a control system that shall function independently of the character of the surface of a target, for setting on an explosive, which is dropped from an aircraft, a short distance above the target.

Another object of my invention is to provide a reliable explosive to be dropped from an aircraft and set ofi a short distance above the target.

A more specific object of my invention-is to provide an explosive to be projected from aircraft which shall be cooked as it moves between the aircraft and ground, after being dropped, and which shall be set off when it is a short distance above a target.

More generally stated, it is an object of my invention to provide an explosive to be dropped from aircraft which shall without fail explode when only a short distance from target.

In accordance with my invention I provide an explosive having an external shell made up of conducting segments insulated from each other. As such an explosive approaches a large body such as ground, the series capacities between ground and the insulated segments increases. The series capacities are, in the practice of my invention, connected in an oscillation generator circuit mounted in the bomb. As the capacities increase the frequency of the oscillations is decreased or the oscillations are entirely suppressed. The detonating device for the bomb is controlled from the generator. When the frequency of the output of the generator is greater than a preset value the detonating device remains unactuated. When the frequency falls below the value'because the bomb is near ground the bomb isexplodedr i atent In accordance with a further aspect of my invention the oscillation generator is of the electric discharge type and the control mechanism for the detonating cap is supplied through the discharge device of the oscillator. While the bomb remains suspended from the aircraft the generator is deenergized. After the bomb is dropped from the aircraft and has fallen a predetermined distance the generator is energized. However, the anode current of the discharge device is maintained small until the frequency of the oscillations generated is decreased to a low value or the oscillations are entirely suppressed. Thiscondition occurs when the bomb is near ground and at this point the detonating control device in circuit with the discharge device is actuated and the bomb is exploded.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation together with additional objects and advantages thereof will best be understood from the following description of a specific embodiment of my invention when read in connection with the accompanying drawing in which:

Figure 1 is a diagrammatic view of a bomb constructed in accordance with my invention; and

Figs. 2 and 3 are diagrammatic views showing the mechanism for cocking the bomb.

The apparatus shown in'the drawing comprises a bomb 5 having a shell formed of a plurality of conducting segments 7 and 9 separated by an insulating segment 11. Within a hollow region adjacent the nose of the bomb 5 an oscillation generator 13 is disposed. The generator comprises an electric discharge device 15 having an anode 17, a cathode 19 and a control electrode 21. The device is preferably of the high vacuum type but it may be of the gaseous or mercury pool type under certain circumstances.

The anode 17 and the cathode 19 of the discharge device 15 are interconnected through the solenoid 23, a network consisting of a capacitor 27 and the secondary 29 of a transformer 31 in parallel and a power source 33 preferably a battery. The solenoid 23 controls a pin 35 which when actuated impinges on a detonating cap 36 setting off the cap and thus exploding the bomb.

The control electrode 21 of the discharge device 15 is connected to the cathode 19 through a grid resistor37. It is also connected to the cathode through a biasing capacitor '39 and a network consisting of the primary 41 of the transformer 31 and a variable capacitor 43. The cathode 19 of the discharge device 15 is also connected to the conducting segment 7 of the bomb shell which is adjacent the nose and the junction of the biasing capacitor 39 and the variable capacitor 43 is connected to the other segment 9 of the shell. 7

The cathode of the discharge device is heated from a battery 45. One terminal of the battery 45 is connected to one-half 47 of a conducting split ring imbedded in the insulating-shell segment 11 which separates the conducting segments. The other terminal of the battery is connected to one terminal of the cathode 19. The remaining terminal of the cathode is connected to the other half 49 of the split ring. When the bomb 5 is suspended from the aircraft from which it is to be dropped, or when it is in storage, the halves 47 and -49 of the split ring are disconnected and maintain the cathode circuit of the discharge device 15 open. The generator is then deenergized. When the bomb 5 is dropped from aircraft, a nut 51 keyed to the propeller shaft 53 is rotated as the propeller 55 rotates and rises to engage the split ring. The nut assembly is preferably so designed that the nut 51 engages the split ring 47-49 only after the shell has dropped a substantial distance of the order of feet from the aircraft. Explosion of the Patented. Jan. 31, 1961.

3 bomb by reason of the high capacity between the insulated shell segments and the aircraft is thus prevented.

When the nut engages the ring the circuit through the cathode 19 of the discharge device 15 is closed and the generator is energized. The oscillations produced have a frequency determined by the inductance of the transformer and the setting of the variable capacitor 43. By reason of the oscillatory current flowing in the control circuit 213941, 4319 of the discharge device 15, the biasing capacitor is charged so that it impresses a negative potential between the control electrode 21 and the cathode 19 and maintains the current flow in the anode circuit 17-2327, 2933--19 of the discharge device small. The current flowing through the solenoid 23 is therefore too small to actuate the detonator 35-36.

As the bomb approaches ground appreciable series capacities are connected between the control electrode 21 and the cathode 19 of the discharge device 15. The series capacities are connected in a circuit extending from the junction of the biasing capacitor 39 and the variable capacitor 43 through the conductor 57 interconnecting the junction and the upper conducting shell segment 9, the capacity between segment 9 and ground, the capacity between ground and the lower conducting segment 7 and the conductor 59 between the latter segment and the cathode 19. The series capacities are in parallel with the variable capacitor 43. As the total capacity across the primary 41 is increased the frequency of the output of the generator is decreased. The biasing capacitor is therefore, to an extent depending on the decrease in frequency, discharged through the grid resistor 37 and the primary 41 of the transformer 31 and the current flow through the anode circuit of the discharge device is increased. When the anode current reaches a predetermined value the solenoid 23 is energized and the detonating pin 35 is actuated to set off the bomb 5. The variable capacitor 43 may be adjusted to such a value that the bomb is exploded a distance of the order of five to twenty feet above ground.

Although I have shown and described certain specific embodiments of my invention I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the spirit of the appended claims.

I claim as my invention:

1. An aerial bomb comprising a shell-casing enclosing an explosive together with an oscillation generator including a discharge device having a plurality of prinicpal electrodes and a control electrode, means for varying the capacity between said control electrode and one of said principal electrodes as said bomb approaches the ground, thereby to vary the frequency of the oscillations generated by said generator, and means responsive to the output of said generator to explode said explosive when said frequency attains a predetermined magnitude.

2. An aerial bomb comprising a shell-casing enclosing an explosive together with an oscillation generator including a discharge device having a plurality of principal electrodes and a control electrode, means for energizing said generator as said bomb moves between a body above ground, from 'which said bomb is dropped, and ground, means for varying the capacity between said control electrode and one of said principal electrodes as said bomb approaches the ground, thereby to vary the frequency of the oscillations generated by said generator, and means responsive to the output of said generator to explode said explosive when said frequency attains a predetermined magnitude.

3. An aerial bomb comprising a shell-casing enclosing an explosive together with an oscillation generator including a discharge device having a plurality of principal electrodes and a control electrode, means for energizing said generator as said bomb moves between a body above ground, from which said bomb .is dropped, and

ground and when said explosive is at least a predetermined distance from said body, means for varying the capacity between said control electrode and one of said principal electrodes as said bomb approaches the ground, thereby to vary the frequency of the oscillations generated by said generator, and means responsive to the output of said generator to explode said explosive when said frequency attains a predetermined magnitude.

4. An aerial bomb comprising a shell-casing enclosing an explosive together with an oscillation generator including a discharge device having a plurality of principal electrodes and a control electrode, means for increasing the capacity between said control electrode and one of said principal electrodes as said bomb approaches the ground, thereby to decrease the frequency of the oscillations generated by said generator, and means responsive to the output of said generator to explode said explosive when said frequency attains a predetermined magnitude.

5. An aerial bomb comprising a shell-casing enclosing an explosive together with an oscillation generator including a discharge device having a control electrode and a plurality of principal electrodes, electromagnetic means in circuit with said principal electrodes for exploding said explosive, means for energizing said generator as said bomb moves between a body above ground from which said bomb is dropped, and ground, means for varying the frequency of said oscillations as said bomb approaches ground, and means responsive to the oscillations generated by said generator for maintaining the current through said discharge device too small to actuate said exploding means until said bomb is a short distance above ground.

6. An aerial bomb comprising a shell-casing enclosing an explosive together with an oscillation generator including a discharge device having a control electrode and a plurality of principal electrodes, electromagnetic means in circuit with said principal electrodes for exploding said explosive, means for energizing said generator as said bomb moves between a body above ground from which said bomb is dropped, and ground, means for varying the frequency of said oscillations as said bomb approaches ground, and means responsive to the oscillations generated by said generator in circuit with said control electrode and one of said principal electrodes maintaining the current through said discharge device too small to actuate said exploding means until said bomb is a short distance above ground.

7. An aerial bomb comprising a shell-casing enclosing an explosive together with an oscillation generator, electromagnetic means in circuit with said generator for exploding said explosive, means for energizing said generator as said bomb moves between a body above ground from which said bomb is dropped, and ground, and means for varying the frequency of said oscillations as said bomb approaches ground, means responsive to the oscillations generated by said generator for preventing the actuation of said exploding means until said bomb is a short distance above ground.

References Cited in the file of this patent UNITED STATES PATENTS 914,371 Davis Mar. 2, 1909 1,352,542 Schneider Sept. 14, 1920 1,383,106 Hadaway et al. June 28, 1921 2,094,351 Draper et al Sept. 28, 1937 2,100,756 Shepard Nov. 30, 1937 2,137,598 Vos Nov. 22, 1938 2,218,502 Breitenstein Oct. 22, 1940 2,255,245 Ferrel Sept. 9, 1941 FOREIGN PATENTS 644,354 France June 5, 1928 353,627 Great Britain July 30, 1931 91,592 Sweden .Dec. 22, 1937 

